Analytical Study of Barrier-free Door Closer Guide Rail System based on Slider-Crank Mechanism

One of the most important elements of barrier-free design is the door entrance system, particularly door closers. Door closers ensure that doors are easy to operate and do not pose any physical barriers to users. However, existing electro-mechanical door closers are relatively heavy, costly and have reliability issues in cases of power outages. Purely mechanical door closers, such as cam action with guide rail and rack-and-pinion with scissors arm, offer a more affordable option due to simpler design and fewer components used. Static forces and torque with geometrical constraints of the door closer guide rail system are considered in deriving the mathematical expressions of a door closer guide rail system using similar approaches as slider-crank mechanism. The formulation considers the effects of pinion torque of a door closer, installation inputs as design parameters, door angle and efficiency. The mathematical model and experimental results show close agreement. The contribution of this paper is that it demonstrates the underlying physics of the door closer guide rail system, thereby aiding in understanding the door behaviour. Additionally, the model can predict the behaviour of the system under different operating conditions, which can be useful for design and optimization purposes. More importantly, this model can be utilised to identify the most effective strategies in reducing opening forces on doors thereby providing design insights to barrier-free application in the future.